The Stranger Things actress will officially be named the youngest-ever UNICEF Goodwill Ambassador at United Nations Headquarters and the Empire State Building on Tuesday (November 20) – aka World Children’s Day – in New York City.

“It’s a dream come true to become a UNICEF Goodwill Ambassador, “Millie said. “It’s a huge honor to join such an impressive list of people who have supported UNICEF over the years. I am looking forward to meeting as many children and young people as I can, hearing their stories, and speaking out on their behalf.”

In her role, Millie will help raise awareness of children’s rights and issues affecting youth, such as lack of education, safe places to play and learn, and the impact of violence, bullying, and poverty.

On World Children’s Day, children around the world will unite for their rights and “take over” key roles in government, entertainment, and business.

As part of the day, UNICEF is asking supporters to raise their voices in solidarity with the most disadvantaged and vulnerable children by helping “turn the world blue” by doing or wearing something blue. ICYMI, check out the short videoMillie starred in to kick-start the activation last week!